Retiring at 55 (or anywhere in your 50s) means solving four problems that a standard "retire at 65" plan doesn't have to: getting to your money penalty-free, paying for health insurance before Medicare, and sequencing withdrawals across a retirement that could easily run 35–40 years instead of 20–25. None of these are individually complicated — but they interact, and modeling them separately is how people end up with a plan that looks fine on paper and falls apart in year three.
If you leave a job in or after the year you turn 55, the IRS lets you withdraw from that employer's 401(k) — not an IRA — without the usual 10% early-withdrawal penalty. It only applies to the plan at the job you just left, and only from 55 to 59½; retire before 55 and you're in 72(t) SEPP territory instead, a stricter set of rules with fixed, locked-in payments for five years or until 59½. The calculator applies the correct rule automatically based on the retirement age you enter.
Medicare doesn't start until 65, so retiring at 55 means 10 years of ACA marketplace coverage, COBRA, or a spouse's plan. Marketplace premiums are subsidized based on income — which creates a real planning lever: keeping your taxable income lower in these years (partly by not over-converting to Roth) can mean a meaningfully larger subsidy. The calculator estimates your ACA premium net of subsidy each year automatically, and caps any Roth conversion so it doesn't accidentally push you over the subsidy cliff.
The years between retiring at 55 and RMDs starting in your 70s are usually your lowest-income stretch ever — often the best window of your life to convert pre-tax dollars to Roth at a low rate. See the Roth conversion guide for how that works in more depth; the short version is that it directly trades off against the ACA subsidy point above, which is exactly the kind of interaction a single-purpose calculator won't catch.
A 35–40 year retirement has to survive more market cycles than a 20-year one, and the order you draw from pre-tax, Roth, and taxable accounts changes your lifetime tax bill substantially. The calculator solves for the mix that covers your target spending each year while comparing dozens of withdrawal-order and bracket-management combinations, then picks whichever leaves the largest ending balance — and it stress-tests the whole plan against a bad early sequence of market returns, which matters more the longer your money has to last.
See a full year-by-year plan for retiring at 55 — Rule of 55, ACA coverage, and withdrawal order, all solved together. Pre-filled with a retirement age of 55; every number is yours to change.
Open the calculator, retiring at 55 →See the FAQ for quick answers on the Rule of 55, 72(t), and related topics, or How the Model Works for the full methodology. For the Roth conversion mechanics mentioned above, see the Roth conversion calculator. If you're also weighing when to claim benefits, see the Social Security claiming optimizer — claiming early alongside an early retirement is its own tradeoff.